In recent years, ischemic heart disease has posed a major problem in an aging population. Of cardiac diseases which are diseases of circulatory organs, myocardial infarction ascribed to cardiovascular disorder, in particular, is a serious, potentially fatal disease which either obstructs the coronary artery or substantially decreases the blood flow resulting in ischemic necrosis of myocytes and deteriorating cardiac function. The direct cause of myocardial infarction is a decrease or interruption of the blood flow to the myocardium due to coronary arteriosclerosis or thrombus formation in the coronary artery. The disease can result in either acute or chronic cardiac failure. Methods adopted for treatment of ischemic heart disease include the dilatation of the obstructed coronary artery by use of an intravascularly inserted balloon, maintenance of blood flow by intravascular insertion of a stent, and dissolution and removal of a thrombus formed in the blood vessel with the use of a thrombolytic agent. With any of such treatments, it is known that as blood flow is restored in the coronary artery, Ca overload or free radicals occur, increasing the region of cellular necrosis. Prevention of the occurrence of such ischemia-reperfusion injury is difficult, and no effective method of treatment has been established.